From 5f307be18b32aeff7bbad540c0d3897ecedbeb56 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 4 Sep 2018 13:18:15 +0200 Subject: asm-generic/tlb, arch: Provide generic tlb_flush() based on flush_tlb_range() Provide a generic tlb_flush() implementation that relies on flush_tlb_range(). This is a little awkward because flush_tlb_range() assumes a VMA for range invalidation, but we no longer have one. Audit of all flush_tlb_range() implementations shows only vma->vm_mm and vma->vm_flags are used, and of the latter only VM_EXEC (I-TLB invalidates) and VM_HUGETLB (large TLB invalidate) are used. Therefore, track VM_EXEC and VM_HUGETLB in two more bits, and create a 'fake' VMA. This allows architectures that have a reasonably efficient flush_tlb_range() to not require any additional effort. No change in behavior intended. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Cc: Andrew Morton Cc: Andy Lutomirski Cc: Aneesh Kumar K.V Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Nick Piggin Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- include/asm-generic/tlb.h | 95 +++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 83 insertions(+), 12 deletions(-) (limited to 'include') diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index f0aa53db5e60..e6a4c407be6c 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -95,7 +95,7 @@ * flush the entire TLB irrespective of the range. For instance * x86-PAE needs this when changing top-level entries. * - * And requires the architecture to provide and implement tlb_flush(). + * And allows the architecture to provide and implement tlb_flush(): * * tlb_flush() may, in addition to the above mentioned mmu_gather fields, make * use of: @@ -111,7 +111,10 @@ * * - tlb_get_unmap_shift() / tlb_get_unmap_size() * - * returns the smallest TLB entry size unmapped in this range + * returns the smallest TLB entry size unmapped in this range. + * + * If an architecture does not provide tlb_flush() a default implementation + * based on flush_tlb_range() will be used. * * Additionally there are a few opt-in features: * @@ -245,6 +248,12 @@ struct mmu_gather { unsigned int cleared_puds : 1; unsigned int cleared_p4ds : 1; + /* + * tracks VM_EXEC | VM_HUGETLB in tlb_start_vma + */ + unsigned int vma_exec : 1; + unsigned int vma_huge : 1; + unsigned int batch_count; struct mmu_gather_batch *active; @@ -286,8 +295,59 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb) tlb->cleared_pmds = 0; tlb->cleared_puds = 0; tlb->cleared_p4ds = 0; + /* + * Do not reset mmu_gather::vma_* fields here, we do not + * call into tlb_start_vma() again to set them if there is an + * intermediate flush. + */ +} + +#ifndef tlb_flush + +#if defined(tlb_start_vma) || defined(tlb_end_vma) +#error Default tlb_flush() relies on default tlb_start_vma() and tlb_end_vma() +#endif + +static inline void tlb_flush(struct mmu_gather *tlb) +{ + if (tlb->fullmm || tlb->need_flush_all) { + flush_tlb_mm(tlb->mm); + } else if (tlb->end) { + struct vm_area_struct vma = { + .vm_mm = tlb->mm, + .vm_flags = (tlb->vma_exec ? VM_EXEC : 0) | + (tlb->vma_huge ? VM_HUGETLB : 0), + }; + + flush_tlb_range(&vma, tlb->start, tlb->end); + } +} + +static inline void +tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) +{ + /* + * flush_tlb_range() implementations that look at VM_HUGETLB (tile, + * mips-4k) flush only large pages. + * + * flush_tlb_range() implementations that flush I-TLB also flush D-TLB + * (tile, xtensa, arm), so it's ok to just add VM_EXEC to an existing + * range. + * + * We rely on tlb_end_vma() to issue a flush, such that when we reset + * these values the batch is empty. + */ + tlb->vma_huge = !!(vma->vm_flags & VM_HUGETLB); + tlb->vma_exec = !!(vma->vm_flags & VM_EXEC); } +#else + +static inline void +tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { } + +#endif + static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) { if (!tlb->end) @@ -357,19 +417,30 @@ static inline unsigned long tlb_get_unmap_size(struct mmu_gather *tlb) * the vmas are adjusted to only cover the region to be torn down. */ #ifndef tlb_start_vma -#define tlb_start_vma(tlb, vma) \ -do { \ - if (!tlb->fullmm) \ - flush_cache_range(vma, vma->vm_start, vma->vm_end); \ -} while (0) +static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) +{ + if (tlb->fullmm) + return; + + tlb_update_vma_flags(tlb, vma); + flush_cache_range(vma, vma->vm_start, vma->vm_end); +} #endif #ifndef tlb_end_vma -#define tlb_end_vma(tlb, vma) \ -do { \ - if (!tlb->fullmm) \ - tlb_flush_mmu_tlbonly(tlb); \ -} while (0) +static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) +{ + if (tlb->fullmm) + return; + + /* + * Do a TLB flush and reset the range at VMA boundaries; this avoids + * the ranges growing with the unused space between consecutive VMAs, + * but also the mmu_gather::vma_* flags from tlb_start_vma() rely on + * this. + */ + tlb_flush_mmu_tlbonly(tlb); +} #endif #ifndef __tlb_remove_tlb_entry -- cgit v1.2.3-59-g8ed1b